Circuit breaker with slidably removable arc extinction chamber



United States Patent 4 Claims. c|. 200-144) This invention is concerned with electrical circuit breakers, and more especially to improvements in the arrangements by which such circuit breakers, especially those of high current-interrupting capacity and provided with so-called arc extinction chambers, may have their extinction-chamber parts readily and quickly removed from the remainder of the structure. Such removal is often necessary for permitting examination of the contacts and other parts of the breaker such as the blow out coils, arcing horns, and the like.

The invention achieves the objective noted in a very simple fashion, by dividing the chamber as a whole into two separable parts, one of which, and by preference the upper part, being bodily removable from the lower part by a simple forward sliding motion. To this end, the chamber side plates themselves are divided, substantially in a horizontal plane, and the mating edges of the side plates in said plane are formed with rabbets, so that the upper part of the extinction chamber can slide forwardly on the lower, just as a drawer slides along its rails. A quick-releasable but secure fastener serves to hold the upper section of the arc chamber in its condition of use, but permits very easy disassembly for inspection or maintenance work.

A preferred embodiment of the invention will now be described, by way of example and not for purpose of limita-tion; the description refers to the appended drawings, in which:

FIG. 1 is a side elevational view of the arc-extinction chamber portion of a circuit breaker.

FIG. 2 is a front elevation view thereof.

In these figures, numeral 1 designates the upper (movable) section of the arc-extinction chamber, and numeral 2 indicates the lower section which is aflixed to the framework of the breaker as a whole. Part or section 1 contains a plurality of metal plates 3 forming flame-cooling screens and intended to de-ionize gases escaping upwardly through the chamber, as well understood by those skilled in the art. Part 1 also carries with it a section 4 containing additional flame-cooling plates 5.

The upper part 1 includes two main or side plates 6 and 7 formed of electrical insulating material, while the lower section 2 includes a similar pair of side plates 8 and 9. In prior art constructions, the plates 6 and 8 would form a single side plate, as would plates 7 and 9. However, such an integral construction would greatly hamper the disassembly of the arc-extinction chamber from around the contacts, blow-out coils and other parts. In accordance with the present invention, the line of division or separation of the side plate structures lies in the horizontal plane, and the mating edges of the upper and lower plates are formed with the rabbets 10 and 11 (see especially FIG. 2) so that the movable or slidable upper chamber section 1 can be slid forwardly along the rails provided by the interfitting plate edges.

Patented June 15, 1965 The lower chamber section 2 is, as stated, fixed to the remainder of the circuit breaker mechanism by a support or bracket 12. A tongue 13 having a limited flexibility is mounted between bracket 12 and the lower section 2, and carries a taper-tipped locating pin 14 which aids in guiding and locating the upper section 1, as it is pushed back into seated position, by entering a recess 15 in the back plate of the latter. Lower section 2 includes, in the example being described, the two are horns 16 and 17, the first of these being connected, by a conductor 18, to the winding of a blow-out coil 19. The other end of this winding is attached through a conductor 20 and the switch blade 21 to a pair of jaws (not shown) which establish the electrical connection to one pole of the breaker. Conventional blowing cheeks 22 aid in creating the magnetic field necessary to repel the are formed upon circuit breaking, and to drive the arc upwards where it will be extinguished with the air of the cooling plates, as known in the art.

To secure the slidable chamber section 1 positively in its seated position, a pair of spring clamp devices 23 are mounted on the opposite side plates 8 and 9, for example, as by passing through rotatable studs 24 with their extremities received in holes in fixed studs such as 26. A spring and washer assembly 28 for each clamp urges it leftward in FIG. 1, so that an intermediate hooked part 30 will urge the side plates 6 and 7 of the sliding section in that direction, as by engaging in notches 32 in the forward edges of such plates. Turned-over forward ends of the clamps enable them to be lifted forward, against the pressure of the springs, so that their tail ends withdraw from the fixed studs 26 allowing the clamps to be turned downwardly for free removal of the section 1 in a forward direction. Upon return of the chamber, pin 14 assures that the tail end (at the left) will be positioned with the rabbets in engagement.

While the invention has been described in detail so that those skilled in this art may practice the same, it will be understood that such details are not intended to limit the scope of the invention, which is defined in the claims.

What is claimed is:

1. A circuit breaker including a fixed and a movable contact, said breaker having two superposed assemblies in horizontal rectilinear sliding relation with one another, the uppermost assembly including a removable arc extinction structure comprising two insulating sidewalls and a plurality of plates connected between said sidewalls, the lowermost assembly having mounted therein at least one of said contacts and including two insulating sidewalls respectively parallel to said first-mentioned pair of sidewalls, rabbeted edges on cooperating sidewalls supporting and guiding said first-mentioned sidewalls for horizontal removal of said are extinction structure, and means for releasably securing the uppermost assembly upon the lowermost assembly.

2. A circuit breaker in accordance with claim 1 in which said securing means includes at least one spring clamp positioned normally to exert a downward and rearward force upon the uppermost assembly.

3. A circuit breaker as claimed in claim 1 wherein said securing means further includes a pair of spring clamp devices mounted on opposite sides of said lowermost assembly and means for urging said clamps for engagement with said uppermost assembly.

4. A circuit breaker in accordance with claim 1, in which the uppermost assembly includes a rear wall having a recess therein, and a locating pin supported by said lowermost assembly in position to cooperate with said recess to locate the position of said uppermost assembly when the latter is fully assembled upon said lowermost assembly.

References Cited by the Examiner UNITED STATES PATENTS 1,398,981 12/21 Trit-le 200----144 t 4 2,646,481 7/53 Wood et al. 200147 2,866,043 12/58 Dickinson et al. 200-447 2,967,921 1/61 Carver 200-144 F FOREIGN PATENTS 561,334 '10/57 Belgium.

' 1,211,435 10/59 France.

1,056,697 5/59 Germany.

10 BERNARD A. GILHEANY, Primary Examiner.

MAX L. LEVY, Examiner. 

1. A CIRCUIT BREAKER INCLUDING A FIXED AND A MOVABLE CONTACT, SAID BREAKER HAVING TWO SUPERPOSED ASSEMBLIES IN HORIZONTAL RECTILINEAR SLIDING RELATION WITH ONE ANOTHER, THE UPPERMOST ASSEMBLY INCLUDING A REMOVABLE ARC EXTINCTION STRUCTURE COMPRISING TWO INSULATING SIDEWALLS AND A PLURALITY OF PLATES CONNECTED BETWEEN SAID SIDEWALLS, THE LOWERMOST ASSEMBLY HAVING MOUNTED THEREIN AT LEAST ONE OF SAID CONTACTS AND INCLUDING TWO INSULATING SIDEWALLS RESPECTIVELY PARALLEL TO SAID FIRST-MENTIONED PAIR OF SIDEWALLS, RABBETED EDGES ON COOPERATING SIDEWALLS SUPPORTING AND GUIDING SAID FIRST-MENTIONED SIDEWALLS FOR HORIZONTAL REMOVAL OF SAID ARC EXTINCTION STRUCTURE, AND MEANS FOR RELEASABLY SECURING THE UPPERMOST ASSEMBLY UPON THE LOWERMOST ASSEMBLY. 